Sedimentation tank



May 6, 1 930. c. 'R. GRlFF| TH 1,

SEDIMENTATION TANK Filed May 10; 1928 2 Sheets-Sheet 2 6 tank of the vals.

Patented M ay 6, 1930 PATENT OFFICE CHARLES R. GRIFFITH, OF SOUTH MANCHESTER, CONNECTICUT SEDIMENTA'IION TANK Application filed May 10,

This invention relates to means for reclaiming valuable matter from domestic sewage and industrial waste waters, andthe primary object is to provide a novel construction of fill and draw type by the use of which the particles of matter in suspension in the water will be precipitated by the action of gravity alone, and the water and sludge may be separately drawn off at proper inter- The invention is illustrated in the accompanying drawings and willbe hereinafter fully described, and it consists in certain novel features which will be particularly pointed out inthe appended claims.

In the drawings:

Figure 1 is a plan view of a tank embodying the invention;

Figure 2 is a central section;

Fig. 3 is 'a sectional charge end of the tank,

Figure 4 is a detail of an inlet,

Figure 5 is a horizontal section.

In the practice of the invention, there is built a concrete tank 1 of oblong form of desired dimensions and the walls of which may have metallic reenforcements embedded therein. At the outlet end of the tank, a sludge-discharge opening 2 is formed through the end wall and a sludge sump 3 is formed in the floor of the tank to discharge through said opening, the floor at being inclined from all points toward said sump, aswill be understood on reference to Figs. 2 and 3. Adjavertical longitudinal elevation of the discent the inlet end of the tank, a weir 5 is built transversely as an integral part of the floor,

a receiving and distributing trough 6 being thereby formed between the weir and the adjacent wall 7 of the tank. Inlet openings 8 are formed through the wall 7 and an influent canal 9 is built along the outer side of said wall to bring the laden water to said openings through which it will flow into the trough in an obvious manner, and a roof 10 is preferably formed over the canal to provide a convenient footing for the attendants although it is obvious the wall 7 may be thick enough to furnish a safe footing. A gate valve 11 of any approved detail form is provided to control the flow through each of the 1928. Serial no. 276,683.

openings 8, each valve being slidably mounted in a guide frame 12 and having a stem 13 rising through the top of the frame. The frames 12 are fixed to the wall, in any approved manner and project above the same, as

shown, and resting on the top bar of each frame is a nut 14 having threaded engagemnet with the upper threaded portion of the respective stem 13. The nut 14 may advantageously take the form of a hand wheel and it will be readily understood that, accordbaflles prevent the inflowing liquid from flowing directly over the weir and direct it to the fioor of the trough so that it will be evenly distributed and will flow over the weir steadily and slowly in a relative thin stream, some agitation of the liquid occurring as a result ofthe impact uponlthe baflles whereby some pulverization of the matters in suspension will be effected.

, Some matter carried by the water will settle upon the floor of the trough and may be washed out from time to time through an opening 16 in one end of' the trough and constituting one terminal of a by-pass 17 in the side wall of the tank. This by-pass discharges into the tank at the inner side of the weir, and a gate-valve 18 is arranged'to cover or uncover the outlet end of the by-pass through the manipulation of a lever 19 which projects above the side wall ofthe tank for convenient operation. It will be understood that if'the valve be set in open position, the

1 of the tank to be eventually delivered into the sludge sump.

Flow through the sludge outlet 2 is conoutlet and carried passes trolled by a gate valve mounted in any convenient manner at the inner end of theb a rod 21 which extends to the to of the adiacent wall and is there connecte to a suitable lever 22 or other settin device. Above the level of the top of the grooved side members 29, and slidably mounted in said side members are a screen and a floating baflie 31, each screen comprising a coarse mesh metallic netting to act as a support and a fine fabric sheet covering I the inner surface of the. netting. The baflie --spaced from'the wall provide channels through which the water through the screens,

may fit in the frame so as to slide easily but the screen should fit closely so that the water must pass through it and can not pass around it, and it will be noted that the screens are by the frames-28 to may pass to the outlets w ile the floating baffle rises and falls with the level of the water to prevent scum and other surface matter adhering to the screen. The screen may be cleaned by passin the opposlte direction or in a downward direction on its inner side. In orderthat the screens ma be raised for inspection or repair, a trol ey frame 32 is erected on the end wall of the tank and a trolley 33 is mounted to travel along the top of said frame, said trolley being equipped with a hoisting cable and a block and tackle 34 which may be engaged with the screen to be raised.

In use the outlets are closed and the inlets are opened and ke t open until the tank is filled whereupon t ey are closed and the body of water permitted to stand in a quiescent state for a period determined by the nature of he liquid being treated. At the end of the settling period, the draw-off valves 1 25 are opened and the water will then pass and flow off through the eflluent canal. The process is then repeated, the inflowing water scouring the floor of the tank and depositing sludge into the sump from by gravity or a pump at given intervals to prevent septic action w '0 should never be permitted, and the periods of withdrawal will depend on the case of domestic sewage or the ike in which the sludge uickly decomposes, the

liquor should never e allowed to remain in the tank beyond the necessary quiescent period. At night or when the flow is low,

water therethrough in.

the nature of the slud e. 111' while others are- 1. Apparatus for the purpose set forth comprising a tank havin for separatel drawing 0 liquor and sludge, inlets exten ing through the opposite end of the tank, a weir adjacent said end, a shallow trough between the inlets and the weir and a by-pass in the lateralside of the tank around the end of the weir and establishinlg1 communication between an end of the troug and the main settling chamber of the tank.

2. Apparatus for the purpose set forth comprising a tank havin means at one end for separately drawing 03 liquor and sludge inlets extending through the opposite end of the tank, a weir adjacent said end, a trough between the inlets and the weir, a by-pass around the end of the weir in the side of the tank establishing communication between an end of the troulgh and the main settling chamber of the tank, a valve controlling flow through the by-pass, and means operable from the top of the tank for setting the valve.

3. Apparatus for comprising a tank having inlets at one end and a sludge sump at t e opposite end, a valved outlet for the sump, valved outlets for liquor above the sump, last-mentioned outlets,- and floating baffles at the inner sides of the screens.

In testimony whereof, I have signed this specification.

- CHARLES R. GRIFFITH.

which act as a filter,

which it is drawn means at one end the purpose set forth screens over the 

